JP2020502309A - Polypropylene and method for producing the same - Google Patents

Abstract

The present invention provides a homopolypropylene having high strength and a low low molecular weight content, as well as excellent processability, and a method for producing the same.

Description

[Cross-reference with related application]
This application claims the benefit of priority from Korean Patent Application No. 10-2017-0159736 filed on November 27, 2017 and Korean Patent Application No. 10-2018-0116448 filed on September 28, 2018. All the contents disclosed in the Korean patent application literature are included as a part of this specification.

  The present invention relates to polypropylene having high strength and low low molecular weight content, as well as excellent processability, and a method for producing the same.

  Olefin polymerization catalyst systems can be classified into Ziegler-Natta and metallocene catalyst systems, and these two highly active catalyst systems have evolved to suit their respective characteristics. Ziegler-Natta catalysts have been widely applied to existing commercial processes since they were invented in the 1950's, but because they are multi-site catalysts with several active sites mixed, the polymer It is characterized by a wide molecular weight distribution, and has a problem that the composition distribution of the comonomer is not uniform and there is a limit in securing desired physical properties.

  On the other hand, metallocene catalysts consist of a combination of a main catalyst composed mainly of a transition metal compound and a cocatalyst composed of an organometallic compound composed mainly of aluminum. Such a catalyst is a homogeneous complex catalyst having a single activity. A single site catalyst, a polymer having a narrow molecular weight distribution and a uniform comonomer composition distribution due to the characteristics of a single active site is obtained, and the ligand structure of the catalyst is changed and the polymerization conditions are changed. There are characteristics that change the tacticity, copolymerization characteristics, molecular weight, crystallinity, etc. of the polymer.

  Normally, homopolypropylene for disposable scourers manufactured using a Ziegler-Natta catalyst has a problem that when the strength is increased or the basis weight is reduced, not only physical properties are lowered but also processability is lowered. In addition, the disposable scourer manufactured with Ziegler-Natta catalyst has a higher xylene solubles than homopolypropylene manufactured with metallocene catalyst and a high content of low molecular weight due to a wide molecular weight distribution. The surface was soft and unsuitable for use on scourers.

  In order to compensate for these drawbacks, polypropylene having a melt index (MI) of 230 g / 10 min, which is conventionally produced using a Ziegler-Natta catalyst, is blended with an additive to spin a coarse feel and a thick fiber. However, a polypropylene composition made with Ziegler-Natta catalyst and a polypropylene composition blended with additives produced non-uniform fibers with poor spinnability, thereby resulting in reduced physical properties. . In addition, there is a drawback that dry blending → thermal processing → pelletizing → second processing → products leads to high processing costs.

  Therefore, the present invention provides a homopolypropylene having high strength and low low molecular weight content with excellent processability by using a metallocene catalyst having a specific structure instead of the Ziegler-Natta catalyst, and a method for producing the same. Aim.

According to one embodiment of the present invention, there is provided a homopolypropylene satisfying the following conditions:
i) Melting index (measured according to ASTM D1238 at 230 ° C. under a load of 2.16 kg) 200 to 2000 g / 10 min
ii) Molecular weight distribution 3.3 or less iii) Residual stress ratio 0.05% or less iv) Xylene soluble matter 1.0% by weight or less

According to another embodiment of the present invention, there is provided a method for producing the homopolypropylene, comprising the step of polymerizing propylene monomer by introducing 700 to 2500 ppm of hydrogen in the presence of a catalyst composition containing a compound of the following Chemical Formula 1. I will provide a:

In the above chemical formula 1,
A is carbon, silicon, or germanium;
X ₁ and X ₂ are each independently halogen,
R ₁ and R ₅ are each independently C _6-20 aryl substituted with C _1-20 alkyl;
R _{2 to} R ₄ and R _{6 to} R ₈ each independently represent hydrogen, halogen, C _1-20 alkyl, C _2-20 alkenyl, C _1-20 alkylsilyl, C _1-20 silylalkyl, _1-20 alkoxysilyl, C _1-20 ether, C _1-20 silyl ether, C _1-20 alkoxy, C _6-20 aryl, C _7-20 alkylaryl, or C _7-20 arylalkyl;
R ₉ and R ₁₀ are the same as each other and are C _2-20 alkyl.

  According to still another embodiment of the present invention, there is provided a resin composition for a nonwoven fabric containing the homopolypropylene, and a nonwoven fabric produced using the same, more specifically, a nonwoven fabric for cleaning such as scourers.

  The homopolypropylene according to the present invention exhibits excellent processability by having a low residual stress ratio and a xylene-soluble content, an optimum range of a melting index and a narrow molecular weight distribution, and is capable of producing a uniform fiber having a small thickness. Production of high rigidity low basis weight nonwoven fabric is possible. In addition, it is possible to provide a rougher feel than existing products, and it is possible to simultaneously realize excellent toughness that is not easily broken even at high strength. This is useful for the production of nonwoven fabrics that require high rigidity and large surface roughness, especially nonwoven fabrics for cleaning such as scourers.

  The terms used in the specification are merely used to describe illustrative embodiments and are not intended to limit the invention. The singular expression includes the plural unless the context clearly indicates otherwise. As used herein, terms such as "comprising", "comprising" or "having" are intended to specify the presence of implemented features, steps, components, or combinations thereof, It is to be understood that the possibility of the presence or addition of one or more other features or steps, components or combinations thereof is not excluded in advance.

  Since the present invention can have various forms with various modifications, the present invention will be described in detail with reference to specific embodiments. It should be understood, however, that this is not intended to limit the invention to the particular disclosure and that it includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

  Hereinafter, a homopolypropylene according to a specific embodiment of the present invention and a method for producing the same will be described.

  In order to supplement the physical characteristics of a disposable scourer conventionally produced with a Ziegler-Natta catalyst, the present invention homogenizes propylene by polymerizing propylene under a controlled content of hydrogen and using a metallocene catalyst described below. By producing polypropylene, the molecular weight distribution of the produced homopolypropylene is narrow and has low residual stress, and it is possible to produce uniform fibers with a small thickness, and as a result, a high rigidity low basis weight nonwoven fabric Can be manufactured. In addition, the homopolypropylene to be produced has a narrow molecular weight distribution and a low content of low molecular weight due to low xylene solubles, so it can provide a rough feel to the surface, and as a result, when applied to a nonwoven fabric for cleaning, The cleaning effect can be improved. Furthermore, since the produced homopolypropylene does not need to be blended with an additive, a nonwoven fabric can be produced only by the primary processing, and the processability can be improved.

Specifically, the homopolypropylene according to one embodiment of the present invention satisfies the following conditions:
i) Melting index (measured according to ASTM D1238 at 230 ° C. under a load of 2.16 kg) 200 to 2000 g / 10 min
ii) Molecular weight distribution 3.3 or less iii) Residual stress ratio 0.05% or less iv) Xylene soluble matter 1.0% by weight or less

  More specifically, the homopolypropylene according to one embodiment of the present invention has a melt index (MI, melt index) measured at 230 ° C. under a load of 2.16 kg of 200 to 2000 g / 10 min according to ASTM D1238. The MI can be adjusted according to the amount of hydrogen supplied during the polymerization step. However, the homopolypropylene according to the present invention has an MI within the above range in consideration of the physical property requirements of ii) to iv). Thereby, spinnability and strength of the nonwoven fabric can be improved in a well-balanced manner. In particular, when processing a nonwoven fabric using homopolypropylene, if MI is less than 200 g / 10 min, the processing pressure may increase and processability may decrease. It is difficult to achieve high strength. In addition, in order to produce a polypropylene having an MI value in the above range, when a Ziegler-Natta catalyst is used, a high content of hydrogen must be introduced in the polymerization stage, but a catalyst containing a metallocene compound as described later is used. By using, it is possible to input a relatively low content of hydrogen, so that there is an advantage that activity control is easy and process stability is enhanced. When considering the spinnability and the nonwoven fabric strength improving effect by the MI control, the MI of the homopolypropylene may be 220 to 1500 g / 10 min.

  Further, the homopolypropylene according to an embodiment of the present invention has a narrow molecular weight distribution (MWD = Mw / Mn) of 3.3 or less together with the MI. By having such a narrow molecular weight distribution, excellent rigidity can be exhibited during the production of the nonwoven fabric. More specifically, the homopolypropylene may have a MWD of 1.5 to 3.3, and even more specifically, 2.5 to 3.3.

  On the other hand, in the present invention, the molecular weight distribution (MWD) is determined by measuring the weight average molecular weight (Mw) and the number average molecular weight (Mn) using gel permeation chromatography (GPC), and then measuring the ratio of the weight average molecular weight to the number average molecular weight. (Mw / Mn). Specifically, it can be measured using a Waters PL-GPC220 instrument using a Polymer Laboratories PLgel MIX-B 300 mm long column. At this time, the evaluation temperature is 160 ° C., and 1,2,4- Trichlorobenzene is used as a solvent, and the flow rate is 1 mL / min. After adjusting the concentration of the sample to 10 mg / 10 mL, the sample is supplied in an amount of 200 μL. Mw and Mn values are derived using a calibration curve formed utilizing polystyrene standards. At this time, the molecular weight (g / mol) of the standard polystyrene was 2,000 / 10,000 / 30,000 / 70,000 / 200,000 / 700,000 / 2,000,000 / 4,000,000. Nine kinds of / 10,000,000 were used.

  Further, the homopolypropylene according to one embodiment of the present invention has a low residual stress ratio of 0.05% or less together with MI and MWD as described above.

  The residual stress ratio can be checked for fiber workability by a rheological property test under an environment similar to the nonwoven fabric manufacturing process, and a stress relaxation test (stress relaxation test) for applying a large strain to homopolypropylene is performed. From the residual stress value measured at this time, it can be calculated by the following equation 1.

[Formula 1]
Residual stress ratio = (RS ₁ / RS ₀ ) × 100
In the above formula 1, RS ₀ is the residual stress at a certain point (t ₀ ) less than 0.05 seconds after applying 200% deformation to the homopolypropylene at 235 ° C., and RS ₁ is 235 This is the residual stress at a point in time (t ₁ ) between 0.05 and 1.50 seconds after 200% deformation of the homopolypropylene at 0 ° C.

In the above formula 1, RS ₀ indicates the residual stress immediately after a 200% deformation of the homopolypropylene at 235 ° C. [for example, at a certain point (t ₀ ) of less than 0.05 seconds]. Then, in Equation 1, RS ₁ is within about 1.5 seconds after the t ₀ under the same conditions as the RS ₀ [for example, a certain time point between 0.05 seconds to 1.50 seconds ( t ₁ )].

Specifically, in Equation 1, wherein t ₀ is 0.01 seconds, or 0.015 seconds, or 0.02 seconds, or 0.025 seconds, or 0.03 seconds, or 0.035 seconds, Alternatively, 0.04 seconds or 0.045 seconds is selected. In the above formula 1, t ₁ is 0.05 seconds, 0.10 seconds, 0.20 seconds, 0.30 seconds, 0.40 seconds, 0.50 seconds, or 0.60 seconds. Seconds, or 0.70 seconds, or 0.80 seconds, or 0.90 seconds, or 1.00 seconds, or 1.10 seconds, or 1.20 seconds, or 1.30 seconds, or 1.40 seconds, Alternatively, it is selected from 1.50 seconds. Preferably, in the measurement of the residual stress, in order to easily secure valid data, in Expression 1, t ₀ is 0.02 seconds, and t ₁ may be advantageously 1.00 seconds. .

  The residual stress ratio of the homopolypropylene is measured in an environment (for example, 235 ° C.) similar to the process conditions for performing melt blowing during the production of the nonwoven fabric. The temperature of 235 ° C. corresponds to a temperature suitable for completely dissolving the homopolypropylene composition and performing meltblowing.

  Usually, a nonwoven fabric is produced by spinning a fiber in a molten state of a resin and performing a drawing step in a semi-molten state by cooling. At this time, when the residual stress ratio according to Equation 1 is as high as more than 0.05%, high resistance to deformation is exhibited, so that the spinning process has poor spinnability, and a thin but uniform fiber. Is difficult to manufacture. In addition, since the yarn breakage occurrence rate is high, the processability is deteriorated, for example, the time during which the fiber cannot be produced due to the yarn breakage during the fiber generation process is reduced, and it is difficult to continuously execute the spinning process. Furthermore, since the web formation is poor, the strength may be reduced.

  On the other hand, the homopolypropylene according to the present invention has a low residual stress ratio of 0.05% or less, so that it is possible to produce a uniform fiber having a small thickness, and has excellent workability and high rigidity. The production of basis weight nonwoven fabric is possible.

  When considering the effect of improving the fiber workability by controlling the residual stress ratio, the residual stress ratio of the homopolypropylene is more specifically 0.005 to 0.05%, still more specifically 0.005 to 0.05%. It may be 0.03%, or 0.02 to 0.03%.

  Further, the homopolypropylene has a high tacticity of 1.0% by weight or less in xylene solubles (Xs).

  In the present invention, the xylene-soluble component is obtained by dissolving homopolypropylene in xylene, crystallizing an insoluble portion from a cooling solution, and calculating a content (% by weight) of a soluble polymer in the crystallized cooling xylene. The xylene solubles contain low stereoregular polymer chains. Thus, the lower the content of the xylene-soluble component, the higher the stereoregularity. The homopolypropylene according to an embodiment of the present invention has such a high stereoregularity, so that it can exhibit excellent rigidity when manufacturing a nonwoven fabric. When considering the improvement effect by controlling the xylene-soluble content, the xylene-soluble content of the homopolypropylene is more specifically 0.5 to 1.0% by weight, and even more specifically, 0.1 to 1.0% by weight. It may be 6 to 0.7% by weight.

  In addition, in the present invention, the xylene-soluble component is prepared by adding xylene to a homopolypropylene sample, heating at 135 ° C. for 1 hour, pre-cooling for 30 minutes, and using an OminiSec (FIPA from Viscotek) at 1 mL / mL. Xylene is flowed for 4 hours at a flow rate of min, and RI (Refractive Index), DP (Pressure cross middle of bridge), and IP (Inlet pressure through line top to bottom stabilization). Then, the concentration and the injection amount of the pretreated sample are entered and measured, and then the peak area can be calculated.

  Further, along with the MI, MWD, residual stress ratio, and xylene solubles conditions described above, the homopolypropylene can have a melting point (Tm) of 150-155 ° C, more specifically 152-154 ° C. When it has a Tm within the above range, excellent spinnability and productivity can be exhibited.

  Meanwhile, in the present invention, the melting point can be measured by using a differential scanning calorimeter (DSC). Specifically, after raising the temperature of the homopolypropylene to 200 ° C., maintaining the temperature for 5 minutes, then lowering the temperature to 30 ° C., then raising the temperature again, and using DSC (Differential Scanning Calorimeter, The peak of the curve can be measured as the melting point. At this time, the rate of temperature rise and fall is 10 ° C./min, respectively, and the melting point is the result of measurement in the second temperature rise section.

  The homopolypropylene according to an embodiment of the present invention having such physical characteristics has a hydrogen content of 700 to 700 wt% based on the total weight of the propylene monomer in the presence of a catalyst composition containing a compound of the following chemical formula 1 as a catalytically active component. Produced by a production method including the step of polymerizing propylene monomer at a dosage of 2500 ppm:

In the above chemical formula 1,
A is carbon, silicon, or germanium;
X ₁ and X ₂ are each independently halogen,
R ₁ and R ₅ are each independently C _6-20 aryl substituted with C _1-20 alkyl;
R _{2 to} R ₄ and R _{6 to} R ₈ each independently represent hydrogen, halogen, C _1-20 alkyl, C _2-20 alkenyl, C _1-20 alkylsilyl, C _1-20 silylalkyl, _1-20 alkoxysilyl, C _1-20 ether, C _1-20 silyl ether, C _1-20 alkoxy, C _6-20 aryl, C _7-20 alkylaryl, or C _7-20 arylalkyl;
R ₉ and R ₁₀ are the same as each other and are C _2-20 alkyl.

  In this specification, unless stated otherwise, the following terms are defined as follows.

  The halogen (halogen) may be fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).

The C _1-20 alkyl group may be a straight, branched or cyclic alkyl group. Specifically, a C _1-20 alkyl group is a C _1-15 linear alkyl group; a C _1-10 linear alkyl group; a C _1-5 linear alkyl group; a C _3-20 branched or cyclic alkyl group. A C _3-15 branched or cyclic alkyl group; or a C _3-10 branched or cyclic alkyl group. More specifically, the C _1-20 alkyl group is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an iso-butyl group, a tert-butyl group, an n-pentyl group. , An iso-pentyl group, a neo-pentyl group, or a cyclohexyl group.

The C _2-20 alkenyl group may be a straight, branched or cyclic alkenyl group. Specifically, the C _2-20 alkenyl group is a C _2-20 linear alkenyl group, a C _2-10 linear alkenyl group, a C _2-5 linear alkenyl group, a C _3-20 branched alkenyl group, It may be a C _3-15 branched alkenyl group, a C _3-10 branched alkenyl group, a C _5-20 cyclic alkenyl group, or a C _5-10 cyclic alkenyl group. More specifically, the C _2-20 alkenyl group may be an ethenyl group, a propenyl group, a butenyl group, a pentenyl group, a cyclohexenyl group, or the like.

C _6-30 aryl can mean a monocyclic, bicyclic or tricyclic aromatic hydrocarbon. Specifically, the C _6-30 aryl may be a phenyl group, a naphthyl group, an anthracenyl group, or the like.

C _7-30 alkylaryl can mean a substituent in which one or more hydrogens of an aryl is replaced by an alkyl. Specifically, _C7-30 alkylaryl is methylphenyl, ethylphenyl, n-propylphenyl, iso-propylphenyl, n-butylphenyl, iso-butylphenyl, tert-butylphenyl, cyclohexylphenyl, or the like. You may.

C _7-30 arylalkyl can mean a substituent in which one or more hydrogens of the alkyl have been replaced by an aryl. Specifically, the _C7-30 arylalkyl may be a benzyl group, phenylpropyl, or phenylhexyl and the like.

  A catalyst composition used for preparing a homopolypropylene according to an embodiment of the present invention includes the compound of Formula 1 as a single catalyst. As a result, the molecular weight distribution may be significantly narrower than a homopolypropylene conventionally produced when two or more catalysts are used in combination.

  Further, the compound of Formula 1 includes a bivalent functional group A disubstituted with the same alkyl group having 2 or more carbon atoms as a bridge group connecting two ligands including an indenyl group, thereby increasing the atomic size. As the solubility angle increases and the solubility angle increases, the monomer can be easily accessed, and a better catalytic activity can be exhibited.

In addition, both of the two indenyl groups of the ligand are substituted with a methyl group at the second position, and the fourth position (R ₁ and R ₅ ) contains an alkyl-substituted aryl group, so that sufficient electrons can be supplied. An excellent catalytic activity can be exhibited by the inductive effect.

  Further, the compound of Formula 1 includes zirconium (Zr) as a central metal, and thus has more orbitals capable of accommodating electrons as compared with the case of including other Group 14 elements such as Hf. As a result, it is possible to easily bind to the monomer with a higher affinity, and as a result, it is possible to exhibit a more excellent effect of improving the catalytic activity.

More specifically, in Formula 1, R ₁ and R ₅ may each independently be a C _6-12 aryl group substituted with C _1-10 alkyl, or more specifically May be a phenyl group substituted with a C _3-6 branched alkyl group such as tert-butylphenyl. Further, the substitution position of the alkyl group with respect to the phenyl group may be the R ₁ or R ₅ position bonded to the indenyl group and the fourth position corresponding to the para position.

In Formula 1, R _{2 to} R ₄ and R _{6 to} R ₈ may each independently be hydrogen, and X ₁ and X ₂ each independently represent chloro. Is also good.

In the chemical formula 1, A may be silicon (Si), and R ₉ and R ₁₀ of the substituents of A may be mutually different from the viewpoint of increasing the solubility and improving the carrying efficiency. It may be the same and may be a C _2-10 alkyl group, more specifically a C _2-4 linear alkyl group, and even more specifically each may be ethyl. As described above, by having the same alkyl group as a substituent for A in the bridge group, when the substituent for the element of the conventional bridge group is a methyl group having 1 carbon atom, the solubility is not good when preparing a supported catalyst. The problem that the loading reactivity decreases can be solved.

  Representative examples of the compound represented by Formula 1 are as follows:

  The compound of Formula 1 is synthesized by applying a known reaction. For a more detailed synthesis method, the production examples described below can be referred to.

  Meanwhile, the compound of Formula 1 may be used as a single component, or may be used in the state of a supported catalyst supported on a carrier.

As the carrier, a carrier having a highly reactive hydroxy group or siloxane group on its surface can be used, and a carrier whose surface has been dried to remove moisture can be used. For example, silica was dried at high temperatures, silica - alumina, and silica - magnesia, etc. can be used, oxidation of these are _{usually, Na 2 O, K 2 CO} 3, BaSO 4, and Mg (NO ₃₎ such as ₂ , Carbonate, sulfate, and nitrate components.

  At the time of drying the carrier, the temperature may be 200 to 800C, or 300 to 600C or 300 to 400C. If the drying temperature of the carrier is too low, there is a risk that the moisture remaining on the carrier is too much and the surface moisture and the co-catalyst react.If the drying temperature is too high, the pores on the carrier surface are combined. As the surface area decreases, more hydroxyl groups are lost on the surface and only siloxane groups remain, which may reduce the number of reaction sites with the cocatalyst.

  As an example, the amount of hydroxy groups on the carrier surface may be 0.1 to 10 mmol / g or 0.5 to 5 mmol / g. The amount of the hydroxy group on the surface of the carrier can be adjusted by the method and conditions for producing the carrier or the drying conditions, such as temperature, time, vacuum or spray drying. If the amount of the hydroxy group is too low, the number of reaction sites with the co-catalyst is small, and if the amount is too large, it may be caused by moisture other than the hydroxyl group present on the surface of the carrier particles.

  In addition, when the compound of Formula 1 is supported on a carrier, the weight ratio of the carrier to the compound of Formula 1 may be 1: 1 to 1: 1000. When the carrier and the compound of Formula 1 are included in the weight ratio, the catalyst may exhibit an appropriate supported catalyst activity, and may be advantageous in terms of maintaining the activity of the catalyst and economical aspects. More specifically, the weight ratio of the carrier to the compound of Formula 1 may be from 1:10 to 1:30, and even more specifically, from 1:15 to 1:20.

  In addition, the catalyst composition may further include a co-catalyst in addition to the compound of Formula 1 and the carrier, from the aspect of improving high activity and process stability. The co-catalyst may include at least one of compounds represented by the following Chemical Formula 2, Chemical Formula 3, or Chemical Formula 4.

[Chemical formula 2]
_{- [Al (R 11) -O} ] m -
In the above chemical formula 2,
R ₁₁ may be the same or different from each other and are each independently a halogen; a C _1-20 hydrocarbon; or a C _1-20 hydrocarbon substituted with a halogen;
m is an integer of 2 or more;
[Chemical formula 3]
J (R ₁₂ ) ₃
In the above chemical formula 3,
R ₁₂ may be the same or different from each other and are each independently a halogen; a C _1-20 hydrocarbon; or a C _1-20 hydrocarbon substituted with a halogen;
J is aluminum or boron;
[Chemical formula 4]
^{[E-H] + [ZQ} 4] - or _{^{[E] + [ZQ 4]}} -
In the above chemical formula 4,
E is a neutral or cationic Lewis base;
H is a hydrogen atom;
Z is a Group 13 element;
Q may be the same as or different from each other, or independently of each other, C ₆ , wherein one or more hydrogen atoms are substituted or unsubstituted with halogen, C _1-20 hydrocarbon, alkoxy or phenoxy; _-20 aryl group or C _1-20 alkyl group.

  Examples of the compound represented by Chemical Formula 2 include methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, and more specifically, methylaluminoxane.

  Examples of the compound represented by Formula 3 include trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, triisopropylaluminum, tri-s-butylaluminum, tricyclopentylaluminum, Pentyl aluminum, triisopentyl aluminum, trihexyl aluminum, trioctyl aluminum, ethyl dimethyl aluminum, methyl diethyl aluminum, triphenyl aluminum, tri-p-tolyl aluminum, dimethyl aluminum methoxide, dimethyl aluminum ethoxide, trimethyl boron, triethyl boron , Triisobutyl boron, tripropyl boron, tributyl boron Etc. include, more specifically, trimethylaluminum, or may be selected from among triethylaluminum, and triisobutylaluminum.

  Examples of the compound represented by Formula 4 include triethylammonium tetraphenylboron, tributylammonium tetraphenylboron, trimethylammonium tetraphenylboron, tripropylammonium tetraphenylboron, trimethylammonium tetra (p-tolyl) boron, Trimethylammonium tetra (o, p-dimethylphenyl) boron, tributylammonium tetra (p-trifluoromethylphenyl) boron, trimethylammonium tetra (p-trifluoromethylphenyl) boron, tributylammonium tetrapentafluorophenylboron, N, N -Diethylanilinium tetraphenylboron, N, N-diethylaniliniumtetrapentafluorophenylboron, diethylammonium Tetrapentafluorophenyl boron, triphenyl phosphonium tetraphenyl boron, trimethyl phosphonium tetraphenyl boron, triethyl ammonium tetraphenyl aluminum, tributyl ammonium tetraphenyl aluminum, trimethyl ammonium tetraphenyl aluminum, tripropyl ammonium tetraphenyl aluminum, trimethyl ammonium tetraphenyl (p -Tolyl) aluminum, tripropylammoniumtetra (p-tolyl) aluminum, triethylammoniumtetra (o, p-dimethylphenyl) aluminum, tributylammoniumtetra (p-trifluoromethylphenyl) aluminum, trimethylammoniumtetra (p-trifluoro) Methylphenyl) aluminum , Tributylammonium tetrapentafluorophenylaluminum, N, N-diethylanilinium tetraphenylaluminum, N, N-diethylanilinium tetrapentafluorophenylaluminum, diethylammonium tetrapentatetraphenylaluminum, triphenylphosphoniumtetraphenylaluminum, trimethylphosphonium Tetraphenylaluminum, tripropylammonium tetra (p-tolyl) boron, triethylammoniumtetra (o, p-dimethylphenyl) boron, tributylammoniumtetra (p-trifluoromethylphenyl) boron, triphenylcarboniumtetra (p-tolyl) Fluoromethylphenyl) boron or triphenylcarbonium tetrapentafluorophene Nilboron and the like, and any one or a mixture of two or more of them can be used.

  When the co-catalyst is further included, the weight ratio of the co-catalyst to the compound of Formula 1 may be 1: 1 to 1:20. When the co-catalyst and the compound of the formula 1 are included in the above weight ratio, the catalyst exhibits appropriate supported catalyst activity, which may be advantageous in terms of maintaining the activity of the catalyst and economical aspects. More specifically, the weight ratio of co-catalyst to compound of Formula 1 may be from 1: 5 to 1:20, and even more specifically, from 1: 5 to 1:15.

  When the catalyst composition includes all of the carrier and the co-catalyst, the catalyst composition includes a step of supporting a co-catalyst compound on a carrier, and a step of supporting the compound represented by Formula 1 on the carrier. In this case, the order of loading the co-catalyst and the compound of Formula 1 can be changed as needed.

  At this time, a hydrocarbon solvent such as pentane, hexane, heptane, or the like, or an aromatic solvent such as benzene, toluene, or the like can be used as a reaction solvent when the catalyst composition is manufactured.

  On the other hand, in the method for producing a homopolypropylene according to one embodiment of the present invention, the polymerization step is performed by bringing a catalyst composition containing the compound represented by the chemical formula 1 into contact with propylene under a hydrogen gas.

  At this time, the hydrogen gas is introduced at a content of 700 to 2500 ppm based on the total weight of the propylene monomer. By adjusting the amount of the hydrogen gas used, it is possible to adjust the molecular weight distribution and the fluidity of the produced homopolypropylene composition within a desired range while exhibiting a sufficient catalytic activity. Thus, a homopropylene polymer having appropriate physical properties can be produced. If the input amount of the hydrogen gas is less than 700 ppm, the MI of the produced homopolypropylene is significantly reduced, and the processability may be reduced. If the amount exceeds 2500 ppm, the MI becomes excessively high, and the production of the nonwoven fabric is increased. At the same time, strength properties and roughness properties may be reduced. More specifically, the hydrogen gas is introduced at a content of 700 ppm or more, or 1500 ppm or more, or 1750 ppm or more, and 2500 ppm or less or 2000 ppm or less.

  The polymerization step is performed in a continuous polymerization step, such as a continuous solution polymerization step, a bulk polymerization step, a suspension polymerization step, a slurry polymerization step, or an emulsion polymerization step, which is known as a polymerization reaction of olefin monomers. Various polymerization processes can be employed. In particular, a continuous bulk-slurry polymerization step is preferred from the viewpoint of obtaining a uniform molecular weight distribution and commercial production of the product.

Further, the polymerization reaction is performed at a temperature of about 40 to 110 ° C. or about 60 to 100 ° C. under a pressure of about 1 to 100 kgf / cm ² .

  Further, in the polymerization reaction, the catalyst is added in a state of being dissolved or diluted in a solvent such as pentane, hexane, heptane, nonane, decane, toluene, benzene, dichloromethane, chlorobenzene and the like. At this time, by treating the solvent with a small amount of alkyl aluminum or the like, a small amount of water or air, which may have an adverse effect on the catalyst, can be removed in advance.

  The homopolypropylene according to an embodiment of the present invention, which is manufactured by the above manufacturing method, has a low residual stress ratio and a xylene-soluble content, and has an MI in an optimum range and a narrow molecular weight distribution. Not only can give a rougher feel than existing products, but also can realize high toughness that is not easily broken with high strength. This is particularly useful in the production of nonwoven fabrics that require high rigidity and large surface roughness, specifically, nonwoven fabrics for cleaning such as scourers.

  Thus, according to still another embodiment of the present invention, there is provided a nonwoven fabric resin composition containing the homopolypropylene and a nonwoven fabric manufactured using the same. At this time, the nonwoven fabric may be a cleaning nonwoven fabric such as a scourer, or more specifically, a disposable scourer.

  The nonwoven fabric resin composition and the nonwoven fabric can be manufactured by a usual method except that the homopolypropylene is used.

  Hereinafter, preferred embodiments will be presented for understanding the present invention. However, the following examples are only for illustrating the present invention, and the contents of the present invention are not limited by the following examples.

(Production Example 1)
Step 1) Preparation of (diethylsilane-diyl) -bis (2-methyl-4- (4-tert-butyl-phenyl) indenyl) silane 2-methyl-4-tert-butyl-phenylindene (20.0 g) was prepared. After dissolving in a toluene / THF volume ratio = 10/1 solution (220 mL), an n-butyllithium solution (2.5 M, hexane solvent, 22.2 g) was slowly added dropwise at 0 ° C., and then added at room temperature. Stirred for days. Diethyldichlorosilane (6.2 g) was slowly added dropwise to the resulting mixed solution at -78 ° C, and the mixture was stirred for about 10 minutes, and further stirred at room temperature for 1 day. Thereafter, water was added to separate the organic layer, and the solvent was distilled under reduced pressure to obtain (diethylsilane-diyl) -bis (2-methyl-4- (4-tert-butyl-phenyl) indenyl) silane.

Step 2) Preparation of [(diethylsilane-diyl) -bis (2-methyl-4- (4-tert-butyl-phenyl) indenyl)] zirconium dichloride (Diethylsilane-diyl) -bis ( After dissolving 2-methyl-4-tert-butyl-phenylindenyl) silane in a toluene / THF volume ratio = 5/1 solution (120 mL), an n-butyllithium solution (2.5 M, hexane solvent, 22 .2g) was slowly added dropwise at -78 ° C and stirred at room temperature for 1 day. A solution prepared by diluting zirconium chloride (8.9 g) in toluene (20 mL) was slowly added dropwise to the resulting reaction solution at -78 ° C, and the mixture was stirred at room temperature for 1 day. After the solvent in the resulting reaction solution was removed under reduced pressure, dichloromethane was added and filtered, and the filtrate was removed by distillation under reduced pressure. After recrystallization using toluene and hexane, rac-[(diethylsilane-diyl) -bis (2-methyl-4- (4-tert-butyl-phenyl) indenyl)] zirconium dichloride (10. 1 g, a yield of 34%, and a weight ratio of rac: meso = 20: 1) were obtained.

Step 3) Production of Supported Catalyst 100 g of silica and a 10% by weight methylaluminoxane solution (670 g, solvent: toluene) were placed in a 3 L reactor and reacted at 90 ° C. for 24 hours. When precipitation was completed after the completion of the reaction, the upper layer solution was removed, and the remaining reaction product was washed twice with toluene. 5.8 g of rac-[(diethylsilane-diyl) -bis (2-methyl-4- (4-tert-butyl-phenyl) indenyl)] zirconium dichloride as the answer metallocene compound prepared in Step 2 was added to 500 ml of toluene. It diluted and added to the said reactor, and it was made to react at 70 degreeC for 5 hours. When precipitation was completed after the completion of the reaction, the upper layer solution was removed, and the remaining reaction product was washed with toluene, washed again with hexane, and dried under vacuum to obtain 150 g of a silica-supported metallocene catalyst in the form of solid particles. .

(Production Example 2)
Instead of the transition metal compound prepared in Step 2 of Preparation Example 1, diethylsilanediyl (2-ethyl-4- (4'-tert-butyl-phenyl) indenyl) (2-methyl-4- (4'- tert-butyl-phenyl) indenyl) zirconium dichloride (Diethylsilandiyl (2-ethyl-4- (4′-tert-butyl-phenyl) -indenyl) (2-methyl-4- (4′-tert-butyl-phenyl) indenyl) A) Silica-supported metallocene catalyst was prepared in the same manner as in Step 3 of Preparation Example 1 except that zirconium dichloride) was used.

(Production Example 3)
Preparation example except that dimethylsilanediylbis (2-methylindenyl) zirconium dichloride (2-methylindenyl) zirconium dichloride was used instead of the transition metal compound prepared in step 2 of Preparation example 1. In the same manner as in Step 3 of Step 1, a silica-supported metallocene catalyst was produced.

(Production Example 4)
Instead of the transition metal compound prepared in Step 2 of Preparation Example 1, dimethylsilanediylbis (2-methyl-4- (4-tert-butylphenyl) indenyl) zirconium dichloride (Dimethylsilanediyl bis (2-methyl-4-) A silica-supported metallocene catalyst was prepared in the same manner as in Step 3 of Preparation Example 1 except that (4-tert-butylphenyl) indenyl) zirconium dichloride was used.

(Production Example 5)
Except for using the compound (I) having the following structure in place of the transition metal compound prepared in Step 2 of Preparation Example 1, a silica-supported metallocene catalyst was prepared in the same manner as in Step 3 of Preparation Example 1. Manufactured.

(Example 1)
In the presence of the metallocene catalyst supported on silica prepared in Preparation Example 1, bulk-slurry polymerization of propylene was carried out using two continuous loop reactors.

  At this time, triethylaluminum (TEAL) and hydrogen gas were respectively supplied at the contents shown in Table 1 below using a pump, and the supported catalyst prepared according to Preparation Example 1 was used in an amount of 30% by weight for bulk-slurry polymerization. It was used in the form of a mud catalyst mixed with oil and grease to obtain a content. The reactor was operated at a temperature of 70 ° C. and a production amount per hour of about 40 kg.

  Specific reaction conditions for the polymerization step of Example 1 are as shown in Table 1 below, and a homopolypropylene was produced by such a polymerization step.

(Examples 2 to 5)
A homopropylene was produced in the same manner as in Example 1 except that the reaction was performed under the conditions shown in Table 1 below.

(Comparative Example 1)
As Z / N homopolypropylene using commercially available H7910 ○ ^R (LG Chemical Co., Ltd.).

(Comparative Examples 2 to 4)
A homopropylene was produced in the same manner as in Example 1 except that the reaction was performed under the conditions shown in Table 1 below.

(Comparative Example 5)
Homopropylene was produced in the same manner as in Example 1 except that 500 ppm of hydrogen was introduced.

(Comparative Example 6)
Homopropylene was produced in the same manner as in Example 1 except that 3000 ppm of hydrogen was introduced.

(Comparative Example 7)
Using the silica-supported metallocene catalyst prepared in Preparation Example 5, homopropylene was prepared in the same manner as in Example 1 except that the reaction was performed under the conditions shown in Table 1 below.

(Test Example 1)
Physical properties of the homopolypropylenes produced in Examples and Comparative Examples were evaluated by the following methods. The results are shown in Table 2 below.

  (1) Melting index (MI, g / 10 min): Measured at 230 ° C. under a load of 2.16 kg according to ASTM D1238, and indicated by the weight (g) of the polymer melted for 10 minutes.

  (2) Xylene solubles (Xylene Soluble, wt%): Each homopolypropylene sample was charged with xylene, heated at 135 ° C. for 1 hour, cooled for 30 minutes, and pretreated. Xylene is flowed at a flow rate of 1 mL / min for 4 hours using a MiniSec (FIPA of Viscotek) equipment, and RI (Refractive Index), DP (Pressure cross-middle toe bleed bridge), and IP (Inlet bleed-through bleed-through bleed). When the base line was stabilized, the concentration and the injection amount of the pretreated sample were recorded and measured, and then the peak area was calculated.

(3) Melting point (Tm, ° C)
After the temperature of the homopolypropylene to be measured is raised to 200 ° C., the temperature is maintained at that temperature for 5 minutes, then lowered to 30 ° C., and the temperature is raised again to obtain a DSC (Differential Scanning Calorimeter, manufactured by TA Company). ) The top of the curve was taken as the melting point. At this time, the rate of temperature rise and fall was 10 ° C./min, and the melting point used was the result measured in the second temperature rise section.

  (4) Molecular weight distribution (MWD, polydispersity index) of the polymer: The molecular weight distribution (“Mw / Mn”) is determined by measuring Mw and Mn using gel permeation chromatography (GPC) and then determining the ratio of Mw / Mn. did. Specifically, the measurement was performed using a Waters PL-GPC220 instrument using a Polymer Laboratories PLgel MIX-B 300 mm long column. At this time, the evaluation temperature was 160 ° C., 1,2,4-trichlorobenzene was used as a solvent, and the flow rate was 1 mL / min. The sample was prepared at a concentration of 10 mg / 10 mL and supplied in a volume of 200 μL. Mw and Mn values were derived using a calibration curve formed utilizing polystyrene standards. The molecular weight (g / mol) of the polystyrene standard is 2,000 / 10,000 / 30,000 / 70,000 / 200,000 / 700,000 / 2,000,000 / 4,000,000 / 10,000. 9,000,000 were used.

(5) Measurement of Residual Stress Ratio A sample was taken of each of the homopolypropylenes according to the examples and the comparative examples, and a change in the residual stress was measured for 10 minutes after applying 200% strain at 235 ° C. did.

  For the measurement of the residual stress, using a Discovery Hybrid Rheometer (DHR) manufactured by TA Instruments, a sample was sufficiently loaded between upper and lower plates (25 mm in diameter), melted at 235 ° C., and then melted at 235 ° C. gap) was fixed at 1 mm and measured.

Based on the measured residual stress data, the residual stress ratio (RS%) was calculated according to the following Equation 1 and shown in Table 2 below:
[Formula 1]
Residual stress ratio (Y) = (RS ₁ / RS ₀ ) * 100
In Equation 1, RS ₀ is the residual stress at 0.02 seconds (t ₀ ) after applying 200% deformation to the sample at 235 ° C., and RS ₁ is 200% at 235 ° C. Is the residual stress at 1.00 seconds (t ₁ ) after the deformation was applied.

  Experimental results show that the homopolypropylenes of Examples 1 to 5 produced by the production method according to the present invention show low xylene solubles and residual stress ratio with narrow MWD and MI in the range of 200 to 2000 g / 10 min. MI increased with increasing hydrogen input. In addition, the homopolypropylenes of Examples 1 to 5 showed significantly reduced xylene solubles and residual stress ratio as compared with the homopolypropylene of Comparative Example 1 produced using a Ziegler-Natta catalyst, and also had a molecular weight distribution. Notably narrow.

  Further, in the case of Comparative Examples 2 to 4 using compounds having different structures as the catalytically active substance, the hydrogen input amount required for producing a polymer having the same level of MI due to the difference in hydrogen reactivity due to the difference in the catalyst structure was reduced. Although different, the molecular weight distribution was increased and the residual stress ratio was significantly increased as compared with Example 1 having the same level of MI. In the case of Comparative Example 7, which has the same ligand structure but uses a compound containing a tether group of alkoxyalkyl as a bridge group connecting two ligands, a high MWD and a high residual stress ratio were exhibited. From this, a reduction in workability can be confirmed.

  In addition, when the same catalyst is not used and the condition of the hydrogen input amount is not satisfied, the melting index is excessively low or high as in Comparative Examples 5 and 6, and a decrease in workability can be confirmed.

(Test Example 2)
<Manufacture of nonwoven fabric>
A spunbonded nonwoven fabric was manufactured by performing a melt blowing process using the resin composition containing the homopolypropylene according to the example and the comparative example.

Specifically, using a 25 mm twin screw extruder, a master batch containing 2000 ppm of Irganox 1010 ^{™ and} 2000 ppm of Irgafos 168 ^™ as antioxidants and homopolypropylene according to Examples and Comparative Examples, and then pelletizing the same. It has become. Next, after feeding the melted master batch composition using a 31 mm Brabender conical twin screw extruder to a melt pump (65 rpm), a soil outlet (10 soil outlets / cm) and a 381 μm soil outlet were used. Reference No. [Report No. 1] except that it was fed to a 25 cm wide meltblowing die having a diameter of 4364 of the Naval Research Laboratories, published May 25, 1954 entitled "Manufacture of Superfine Organic Fibers" by Wente, Van. A. Boone, C.I. D. And Fluharty, E.C. L. The masterbatch pellets were extruded into a microfiber web by a process similar to that described above.

  The melt temperature is 235 ° C., the screw speed is 120 rpm, the die is maintained at 235 ° C., the primary air temperature and pressure are 300 ° C. and 60 kPa (8.7 psi), respectively, and the polymer processing speed is 5 ° C. 0.44 kg / hr and the collector / die distance was 15.2 cm.

<Evaluation of physical properties of nonwoven fabric>
Physical properties of the spunbonded nonwoven fabrics manufactured using the homopolypropylenes of the above Examples and Comparative Examples were evaluated by the following methods, and the results are shown in Table 3 below.

(1) Nonwoven fabric weight (gsm)
The weight of the manufactured nonwoven fabric was measured, and the weight of the nonwoven fabric per unit area was calculated.

(2) Processability of nonwoven fabric During the production of the nonwoven fabric, the presence or absence of fiber breakage was confirmed, and the processability of the nonwoven fabric was evaluated according to the following criteria.
<Evaluation criteria>
Good: when the rate of fiber breakage is 10% or less, that is, when the time during which fiber cannot be produced due to breakage is 2.4 hours or less based on 24 hours of fiber production,
Defective: The rate of occurrence of fiber breakage exceeds 10%, that is, the time during which fiber cannot be produced due to breakage exceeds 2.4 hours based on 24 hours during which fiber is manufactured.

(3) Strength of Nonwoven Fabric According to the method of American Society for Testing and Materials, ASTM D5035: 2011 (2015), the longitudinal direction (MD, machine direction) and the transverse direction (CD, cross direction) of the nonwoven fabric are determined by 5 cm width cut-strip method. ) Was measured (Strength, N / 5 cm).

(4) Roughness of Nonwoven Fabric The roughness of the nonwoven fabric was measured by blind panel evaluation of 10 persons and evaluated according to the following criteria:
<Evaluation criteria>
◎: Judged that the evaluation of the feel of the nonwoven fabric as coarse was excellent when 7 or more people were good. ○: Judged as good when the evaluation of the feel of the nonwoven fabric was rough was 4 to 6 people. Δ: About the feel of the nonwoven fabric. If the evaluation of coarse is 2 or 3 people, it is judged as normal. X: The texture of the nonwoven fabric is judged as poor if the evaluation of being coarse is 1 or less.

  According to one embodiment of the present invention, the nonwoven fabric manufactured using the homopolypropylenes of Examples 1 to 5, in which MI, MWD, xylene-soluble components, and residual stress ratios are all optimized, has high processability, high strength and The roughness was indicated. Furthermore, from the high roughness characteristics of the homopolypropylenes according to Examples 1 to 5, it can be seen that a nonwoven fabric for cleaning requiring high roughness characteristics can be produced only by primary processing without blending with an additive. .

  On the other hand, in the case of Comparative Example 1 manufactured using the Ziegler-Natta catalyst, the workability was poor, and the strength and roughness characteristics were significantly reduced as compared with Examples 1 to 5. In order to produce a nonwoven fabric for cleaning using the homopolypropylene produced according to Comparative Example 1 particularly from the low roughness characteristics, blending with an additive for increasing the roughness characteristics and secondary processing are essential. You can see that.

  Also, in Comparative Examples 2 to 4 using compounds having different structures as the catalytically active substance, compared to Example 1 having the same MI, poor workability was exhibited due to a higher residual stress ratio, resulting in web formation. The strength was poor due to poor web formation.

  In addition, even if the same catalyst was used, in the case of Comparative Example 5 in which the amount of hydrogen input was too low, deviating from the conditions of the amount of hydrogen input, the MI value was lower than 200 g / 10 min, indicating poor workability. On the other hand, in the case of Comparative Example 6 in which the amount of hydrogen input was too high, the roughness characteristic was lowered by the MI exceeding 2000 g / 10 min, and the strength characteristics were also increased by the increase of the MWD and the xylene solubles exceeding 3.3. The value was lower than that of the example.

  Further, in the case of Comparative Example 7 in which a compound having an alkoxyalkyl tether group is used as a bridge group for linking two ligands having the same ligand structure, the produced homopolypropylene has high MWD and residual stress. Indicated poor workability. From these results, it can be confirmed that a transition metal compound having the structure of Chemical Formula 1 is preferable for realizing a homopolypropylene satisfying the physical properties according to the present invention.

Claims (14)

Homopolypropylene meeting the following conditions:
i) Melting index (measured according to ASTM D1238 at 230 ° C. under a load of 2.16 kg) 200 to 2000 g / 10 min
ii) Molecular weight distribution of 3.3 or less iii) Residual stress ratio of 0.05% or less iv) Xylene-soluble content of 1.0% by weight or less.   The homopolypropylene according to claim 1, wherein the homopolypropylene has a molecular weight distribution of 2.5 to 3.3.   The homopolypropylene according to claim 1, wherein the homopolypropylene has a residual stress ratio of 0.02 to 0.03%.   The homopolypropylene according to claim 1, wherein the homopolypropylene has a xylene-soluble content of 0.6 to 0.7% by weight.   The homopolypropylene according to claim 1, wherein the homopolypropylene has a melting point of 150 to 155C. The method for producing a homopolypropylene according to claim 1, comprising a step of introducing 700 to 2500 ppm of hydrogen to polymerize a propylene monomer in the presence of a catalyst composition containing a compound of the following Chemical Formula 1:
In the above chemical formula 1,
A is carbon, silicon, or germanium;
X ₁ and X ₂ are each independently halogen,
R ₁ and R ₅ are each independently C _6-20 aryl substituted with C _1-20 alkyl;
R _{2 to} R ₄ and R _{6 to} R ₈ each independently represent hydrogen, halogen, C _1-20 alkyl, C _2-20 alkenyl, C _1-20 alkylsilyl, C _1-20 silylalkyl, C _{1 -20} alkoxysilyl, _C1-20 ether, _C1-20 silyl ether, _C1-20 alkoxy, _C6-20 aryl, _C7-20 alkylaryl, or _C7-20 arylalkyl;
R ₉ and R ₁₀ are the same as each other and are C _2-20 alkyl.   The method according to claim 6, wherein A is silicon. The method for producing a homopolypropylene according to claim 6, wherein R ₁ and R ₅ are each independently a phenyl group substituted with a C _3-6 branched alkyl group. Wherein R ₉ and R ₁₀ are the same and are C _2-4 linear alkyl group, the manufacturing method of the homopolypropylene of claim 6. The method according to claim 6, wherein R ₉ and R ₁₀ are each ethyl. The method of claim 6, wherein the compound of Formula 1 is a compound represented by Formula 1a below.
  The method of claim 6, wherein the compound of Formula 1 is supported on a carrier. The homogenous composition according to claim 6, wherein the catalyst composition further comprises at least one of a compound represented by the following Chemical Formula 2, a compound represented by the Chemical Formula 3, and a compound represented by the Chemical Formula 4. Production method of polypropylene:
[Chemical formula 2]
_{- [Al (R 11) -O} ] m -
In the above chemical formula 2,
R ₁₁ are the same or different and are each independently a halogen; a C _1-20 hydrocarbon; or a C _1-20 hydrocarbon substituted with halogen;
m is an integer of 2 or more;
[Chemical formula 3]
J (R ₁₂ ) ₃
In the above chemical formula 3,
R ₁₂ are the same or different and are each independently a halogen; a C _1-20 hydrocarbon; or a C _1-20 hydrocarbon substituted with halogen;
J is aluminum or boron;
[Chemical formula 4]
^{[E-H] + [ZQ} 4] - or _{^{[E] + [ZQ 4]}} -
In the above chemical formula 4,
E is a neutral or cationic Lewis base;
H is a hydrogen atom;
Z is a Group 13 element;
Q is the same or different and is each independently a C _6-20 aryl group wherein one or more hydrogen atoms are substituted or unsubstituted by halogen, C _1-20 hydrocarbon, alkoxy or phenoxy Or a C _1-20 alkyl group.   A nonwoven fabric for cleaning comprising the homopolypropylene according to claim 1.